U.S. Pat. No. 3,619,200 relates to chemically modifying pellets and/or using a surface coating therefor. Proteinaceous feed is protected from breakdown within the rumen by the modification of protein itself, by the application of a protective coating to the feedstuff, or by combination of both. Various polymers are disclosed in this patent including copolymers of vinylpyridine and styrene. Canadian Pat. No. 911,649 discloses treatment of proeteinaceous materials with substances which are capable of reacting with proteins to form a polymeric proteinaceous complex on the surface of the material or by treating the proteinaceous material with a polymer or copolymer of a basic vinyl or acrylic monomer. This patent also discloses the use of copolymers and terpolymers derived from essentially a basic substituted acrylate or methacrylate monomer and at least one ethylenically unsaturated compound as rumen stable coatings. U.S. Pat. No. 3,880,990 and British Pat. No. 1,346,739 relate to an orally administratable ruminant composition wherein a medicinal substance is encapsulated or embedded in a normally solid, physiologically acceptable basic polymer. The compositions are produced by dispersing a medicinal substance in a first solvent and adding thereto a second solvent which is miscible with the first solvent but in which the polymer and medicinal substance are substantially insoluble. There is no suggestion of modifying the polymer by the use of additives. U.S. Pat. No. 3,041,243 relates to coatings for oral medicaments. These coatings are water-insoluble but acid-soluble film-forming polymers. An example mentioned in this patent is 2-methyl-5-vinyl pyridine copolymerized with vinyl acetate acrylonitrile, methyl acrylate or styrene.
U.S. Pat. No. 3,697,640 relates to materials such as medicaments and nutrients for ruminants which are coated with nitrogen-containing cellulosic materials such as, for example, cellulose propionate morpholino butyrate. This patent, however, fails to suggest the use of any additives in the nitrogen-containing cellulosic material, and U.S. Pat. No. 3,988,480 relates to a proteinaceous feedstuff for ruminants which has been treated with acetic acid to render it rumen stable.
U.S. Pat. No. 3,383,283 relates to coating pharmaceutical pellets with a plurality of charges of fatty acid as a melt or in solution. The fatty acid may then be dusted with a fine inert powder such as talc. There is no suggestion of using a continuous matrix polymer.
U.S. Pat. No. 3,275,518 relates to a tablet coating composition comprising a film-forming resin or plastic and a hard water-soluble or water-dispersible substance. Stearic acid is mentioned as an optional water-insoluble wax which may be included as an additive. Additional materials such as dyes, pigments, water-insoluble waxes, plasticizing agents, etc., may also be added to the coating. However, the film-forming resin or plastic according to this patent is selected from the group consisting of poly(methylstyrene), methylstyrene-acrylonitrile copolymers, poly(vinylchloride), poly(vinyl butyral), pentaerythritol or alkyd esters of rosin or modified rosin and terpene derived alkyd resins. There is no suggestion of the polymers according to applicants' invention. In fact, the plastic or resin is described as water-permeable, and the coating apparently is not designed for ruminants.
U.S. Pat. No. 3,623,997 relates to a method of sealing polymeric material walls of minute capsules by treating the capsules with a waxy material. The wax is introduced in a solvent which is subsequently dried and the wax is left as a residue in the walls. The capsule walls shrink and lose solvent and then entrap the wax tightly as a sealing material. There is no indication, however, that the polymer coating is designed to function for ruminants, and the wax is used as a sealing material. Applicant's hydrophobic substance is dispersed in the polymer.
U.S. Pat. No. 3,073,748 relates to tablets coated with a solution of an amphoteric film-forming polymer. The polymer is described as one selected from the group consisting of copolymers of (a) vinylpyridines with (b) a lower aliphatic .alpha.,.beta.-unsaturated monocarboxylic acid of 3 to 4 carbon atoms and copolymers of (a), (b) and a neutral comonomer selected from the group consisting of methyl acrylate, acrylonitrile, vinyl acetate, methyl methacrylate and styrene. There is no suggestion of using a dispersed additive.
British Pat. No. 1,217,365 and Canadian counterpart No. 851,128 relate to a particulate feed additive composition for ruminants wherein each particle comprises one or more amino acids totally encased in a continuous film of protective material which is transportable through the rumen without substantial degradation therein but which releases the active substance posterior to the omasum when the particles have a density within the range of 0.8 to 2.0 and diameters in the range of 200 to 2,000 microns. Suggested as protective materials are fatty acid triglycerides such as hydrogenated vegetable and animal fats, waxes such as rice-brand wax, and resin wax blends which are emulsified and/or dissolved in the intestinal tract.